Why "10 metres water-resistant" is not enough for swimming with a watch
When swimming, you only move on the surface of the water. Nevertheless, a watch that is sealed to a depth of 10 metres is very likely to let water in. This information is somewhat misleading.
The degree to which a watch is protected against water is sometimes specified in metres: 50, 100 or 200 metres. But who dives to a depth of 200 metres? Does anyone even need it?
The simple answer: yes. If you want to go swimming with your watch, 100 metres is the minimum to make sure no water gets in. Just like this watch.
Water pressure without movement
Why is that? The indication in metres refers to a certain water pressure. A watch that is water-resistant to 10 metres can withstand the prevailing overpressure of approximately one bar. At 100 metres, it is approximately ten bar. Many watches therefore have specifications in bar instead of metres.
In both cases, however, the watch can only withstand the specified water pressure if it is kept completely still. Movements in the water create additional pressure that can exceed the static pressure many times over. When swimming, for example, the arms are constantly moving, often against high resistance.
How many metres does it take?
And what does this mean in practice? It is not possible to predict exactly how high the actual pressure will be when swimming, snorkelling or high diving. Casio recommends the following:
- Diving (without equipment): 20 bar or 200 metres.
- Swimming, snorkelling on the surface: 10 bar or 100 metres.
- Bathing, washing, showering: 5 bar or 50 metres.
- Rain, water splashes: Water Resist without further specification.
Too late? Not necessarily
If this information comes too late for you, here is some good news: the watch often does not break permanently if water gets in. So just let it dry patiently. My Casio F-91W, which is only protected against splash water, has survived repeated surfing in salt water. However, it didn't work at all or didn't work properly for about two weeks. I almost disposed of it because of this. Today it works perfectly again.
David Lee
Senior Editor
David.Lee@digitecgalaxus.chMy interest in IT and writing landed me in tech journalism early on (2000). I want to know how we can use technology without being used. Outside of the office, I’m a keen musician who makes up for lacking talent with excessive enthusiasm.
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